Mexican blue is a magnificent palm tree that easily handles our extreme sun, wind, and temperature swings. It’s one of the few Sonoran Desert native palms, and it also happens to be an unusual silver-blue. Here’s everything you need to know about planting and caring for this unique desert palm.
Mexican blue palm (Brahea armata) lives up to its moniker of “blue”. It truly is one of the bluest and most attractive palms you can grow in desert gardens. And everything about this palm says “substantial”.
It has a single trunk that is thick at the base, making it squat and sturdy-looking. (This is not a skinny “telephone pole” palm.) It’s covered with gray “elephant hide” bark. When plants mature, each frond can be up to 9 feet across.
In the spring, it puts out massive, cascading flower stalks of creamy white flowers. Flowers are followed by long, pendulous clusters of golden fruits that turn black as they ripen.
And as a Sonoran Desert native, it tolerates temperature extremes and aridity. And it’s so cold hardy, it can be grown in arid regions of Oregon and Washington state!
Why I Like This Plant
- Large silver-blue fronds
- Stunning flower stalks
- Thrives in extreme sun, heat, cold
- Sonoran Desert native
Things to Watch Out For
The leaf stems are lined with surprisingly sharp thorns. When pruning the fronds or otherwise working around this plant, protective gear is advised.
The huge flower stalks put out copious numbers of flowers and fruits that will fall unless you trim them first. Once this tree matures, this is no easy task since stalks can be close to 20 feet long!
Removing the stalks every year is a maintenance task that can be daunting when the tree gets large, and becomes expensive when it becomes impractical for you to do it yourself.
Optimal Growing Conditions
If you’re thinking of adding a Mexican blue palm to your garden, you need to find a suitable place that will keep your plant healthy and looking good… while minimizing maintenance for you.
Here are the key factors to keep in mind.
Temperature
Mexican blue palm should be grown in USDA Hardiness Zones 8 – 11. It thrives in a wide range of temperatures from extreme heat to extreme cold, withstanding temperatures down to 15℉.
Sun Exposure
Mexican blue palms thrive in full sun, including reflected heat, but will also grow in part shade.
Size and Growth Rate
Mexican blue palm is very slow growing when young. It takes about 15 years to reach 5 to 8 feet tall. But with time, the pace picks up.
When mature, you can expect your tree to be approximately 30 feet tall and have a 10 to 15 foot wide canopy.
The trunk is noticeably wider at the base and can have a 3 foot diameter.
Soil
Mexican blue palm grows well in most native soil — rocky, sandy, alkaline, or even caliche — provided it’s well-draining. It grows better in poor, alkaline soil than it does in rich, acidic soil.
Other Location Considerations
Mexican blue palm should not be planted in humid subtropical or tropical climates. It likes it dry!
The stem of each frond is lined with razor-sharp teeth so you might not want to plant it where it might come in contact with curious children or pets.
It’s generally considered a good “pool plant” since it’s low-litter… except when the tree drops its ripe fruits.
It can be grown in a large container, which will help to keep it a manageable size.
Mexican Blue Palm:
The Essentials
| Common Name | Mexican blue palm |
| Scientific Name | Brahea armata |
| Origin | Mexico |
| Plant Type | Palm tree |
| USDA Zones | Zones 8 – 11 |
| Cold Hardiness | To 15℉ |
| Flower Color | Cream |
| Flower Season | Spring, summer |
| Mature Size | 30’ high x 10-15’ wide |
| Growth Rate | Slow |
| Sun Tolerance | Full, part, reflected sun |
| Water Needs | Low |
| Pests & Diseases | None |
| Cautions | Thorns |
How to Plant
The rule of thumb when planting any palm in the desert is to dig a hole two feet wider on each side than the root ball but no deeper.
Amending the soil is not recommended. Counterintuitively, backfilling with the same native soil you just dug up helps your plant develop a stronger root system. Additionally, amending the soil will eventually result in the palm sinking into the hole.
When to Plant
The best time to plant Mexican blue palm is late spring to early summer. Warm soil temperatures encourage root development.
How to Care for Mexican Blue Palm
Whether you’ve recently planted a new fan palm or have an existing one in your yard, here’s how to take care of it to keep it healthy and looking its best.
How to Water
Once you’ve got your palm planted, water thoroughly, and then water daily for the next 2 weeks. Then water every 2 to 3 days for the following 2 weeks and gradually reduce the frequency of watering to get it on this recommended watering schedule for palms.
| Spring & Fall | Every 10 – 14 days |
| Summer | Every 5 – 10 days |
| Winter | Every 14 – 21 days |
Keep in mind that this is a moderate rather than low water use plant. Although it’s a desert native, it naturally occurs where underground water is available. It can survive dry conditions but grows best when the soil stays somewhat moist.
Should You Fertilize?
Mexican blue palm benefits from applications of fertilizer in May and then again in August. There is no point in fertilizing during cooler weather when palms can’t make use of the nutrients.
Look for a slow release fertilizer that contains about 3 times as much nitrogen as potassium and phosphorus.
You’ll find everything you need to know about fertilizing palms, including brands that meet the recommended criteria, in our article How & When to Fertilize Desert Palms.
How to Prune
Mexican blue palm needs very little pruning. Your plant will be healthier if you refrain from removing any green leaves, since they provide the plant’s energy. Wait until they’ve turned brown. You can remove those any time of year.
You can remove flower stalks after they appear. Some gardeners consider their dramatic flower stalks a feature and leave them on the plant as long as they can, while others may want to remove them pre-emptively before the fruits get messy.
Plant Lover Facts
Mexican blue palm (Brahea armata) also goes by the common names blue hesper palm, Mexican blue fan palm, blue fan palm, and gray goddess. (Don’t confuse it with the similarly named Mexican fan palm (Washingtonia robusta), another Sonoran Desert native.)
Mexican blue palm is rare in nature. It grows only in the rocky canyons of Baja California and Sonora, Mexico where underground water is available. It is one of the few palms native to the Sonoran Desert.
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Author Bio
Deane Alban is the creator of Southwest Gardener. She is a science writer with a bachelor’s degree in botany from the University of South Florida. Gardening is her lifelong passion. She’s been gardening in Tucson for over 15 years.
Photo Credits
Arizona State University’s Virtual Library of Phoenix Landscape Plants
Rjcastillo, CC BY-SA 3.0, via Wikimedia Commons
Steve L. Martin, CC BY-SA 2.0, via Wikimedia Commons